Thanks for all the posts guys but i have to disagree with some of the things written, here are my findings with tests carried out so far with a FX5900XT and GeForce 2MX card:
FX5900XT: With my PC config FS2004 works perfectly with AA turned off in the game and on my card. If i select AA in game and not on the card it causes minimal flickering upon loading and a small ammount in game no matter what drivers you use (Forceware, Nvidia, or Omega).
If i switch AA to on on the card so both FS2004 and the card have it the flickering is appaling when loading levels, it is so bad it is like when you degauss a screen but only for the first maybe 5 seconds of loading. It then flickers quite badly when the 2D cockpit loads and then a little during gameplay. If it is turned off in game and switched on on the card to 2x or 4x the flickering is the same as when it was on on the card and in FS2004 so no change there.
I gave up testing the FX5900XT it seemed to have a major compatability issue for me however i suspect my VIA chipset motherboard and maybe going for eg. a nforce chipset on another motherboard may solve the problem but i just dont know.....
GeForce2 MX: This card does not flicker at all using exactly the same PC no matter what settings with AA are used in game or on the card so that shows it is an issue as regards flickering with the FX5900XT.
However the GF2 when using older Nvidia drivers has no 2D panel it is missing and there is just a black space which may be solvable as i have heard reports of this using the older nvidia drivers i am yet to solve this however.
If i use newer nvidia drivers with this card i get massive dials as shown on the screenshot (on my previous posts) with the 2D cockpit however i think this may be due to using an older card with newer drivers and if i solve the black space issue with the older drivers the correct dial size may show up however.
One thing that is interesting is the fact that the larger dials problem is only apparent when using AA with FS2004 so again AA has managed to cause another (completely different) problem.
Also i have just noticed that if i have the problems with the larger dials when using the newer drivers i can make the proper 2D cockpit show up by pressing ALT and then when the sim is paused it shows up correctly but as soon as i press ALT again to play the game the problem returns so i can only have the proper 2D panel with the newer drivers when the game is paused, which of course is really useful NOT!!!???
My Solution: well basically i have had it with Nvidia there is so much grief with nvidia cards from my experience with this game, and i am hoping my computer supplier will allow me to exchange my card for a Radeon 9800pro which i believe is a better card anyway (than my FX5900XT of course!). I also have other issues with nvidia which i wont go into with their latest drivers (and other applications) and although i was an avid nvidia supporter i am planting my flag in the ATI camp now!